Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751430AbaLOLOs (ORCPT ); Mon, 15 Dec 2014 06:14:48 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:53682 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750989AbaLOLOp (ORCPT ); Mon, 15 Dec 2014 06:14:45 -0500 X-SecurityPolicyCheck: OK by SHieldMailChecker v2.2.3 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20140219-2 Message-ID: <548EC29A.5080008@jp.fujitsu.com> Date: Mon, 15 Dec 2014 20:14:34 +0900 From: Kamezawa Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Lai Jiangshan , , Tejun Heo CC: Yasuaki Ishimatsu , "Gu, Zheng" , tangchen Subject: [PATCH 1/4] workqueue:Fix unbound workqueue's node affinity detection References: <1418379595-6281-1-git-send-email-laijs@cn.fujitsu.com> <548C68DA.20507@jp.fujitsu.com> <548EC1E2.1010101@jp.fujitsu.com> In-Reply-To: <548EC1E2.1010101@jp.fujitsu.com> Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit X-SecurityPolicyCheck-GC: OK by FENCE-Mail Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Unbound wq pool's node attribute is calculated at its allocation. But it's now calculated based on possible cpu<->node information which can be wrong after cpu hotplug/unplug. If wrong pool->node is set, following allocation error will happen. == SLUB: Unable to allocate memory on node 2 (gfp=0x80d0) cache: kmalloc-192, object size: 192, buffer size: 192, default order: 1, min order: 0 node 0: slabs: 6172, objs: 259224, free: 245741 node 1: slabs: 3261, objs: 136962, free: 127656 == This patch fixes the node detection by making use of online cpu info. Unlike cpumask, the best node can be calculated by degree of overlap between attr->cpumask and numanode->online_cpumask. This change doesn't corrupt original purpose of the old calculation. Note: it's expected that this function is called as pool_detect_best_node get_unbound_pool alloc_unbound_pwq wq_update_unbound_numa called at CPU_ONLINE/CPU_DOWN_PREPARE and the latest online cpu info can be applied to a new wq pool, which replaces old one. Signed-off-by: KAMEZAWA Hiroyuki --- kernel/workqueue.c | 38 ++++++++++++++++++++++++++------------ 1 file changed, 26 insertions(+), 12 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 09b685d..7809154 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3440,6 +3440,31 @@ static void put_unbound_pool(struct worker_pool *pool) } /** + * pool_detect_best_node - detect a node which contains specified cpumask. + * Should be called with wq_pool_mutex held. + * Returns a online node where the most of given cpus are tied to. + */ +static int pool_detect_best_node(const struct cpumask *cpumask) +{ + int node, best, match, selected = NUMA_NO_NODE; + static struct cpumask andmask; /* under wq_pool_mutex */ + + if (!wq_numa_enabled || + cpumask_subset(cpu_online_mask, cpumask)) + goto out; + best = 0; + /* select a node which contains the most number of cpu */ + for_each_node_state(node, N_ONLINE) { + cpumask_and(&andmask, cpumask, cpumask_of_node(node)); + match = cpumask_weight(&andmask); + if (match > best) + selected = best; + } +out: + return selected; +} + +/** * get_unbound_pool - get a worker_pool with the specified attributes * @attrs: the attributes of the worker_pool to get * @@ -3457,7 +3482,6 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) { u32 hash = wqattrs_hash(attrs); struct worker_pool *pool; - int node; lockdep_assert_held(&wq_pool_mutex); @@ -3482,17 +3506,7 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) * 'struct workqueue_attrs' comments for detail. */ pool->attrs->no_numa = false; - - /* if cpumask is contained inside a NUMA node, we belong to that node */ - if (wq_numa_enabled) { - for_each_node(node) { - if (cpumask_subset(pool->attrs->cpumask, - wq_numa_possible_cpumask[node])) { - pool->node = node; - break; - } - } - } + pool->node = pool_detect_best_node(pool->attrs->cpumask); if (worker_pool_assign_id(pool) < 0) goto fail; -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/